Recent years have witnessed the proliferation of personal media creation and distribution, such as audio podcasting, web logs (“blogs”), RSS (Really Simple Syndication) feeds, web cameras, and the like. With the expanding range of distribution possibilities for such content, the ability to determine and ascertain ownership of content may become more problematic. For example, such content may be edited, re-recorded, sampled or otherwise processed, which may make it difficult to determine the origin of the content.
One way to manage content distribution is to restrict access to it. For example, several techniques for digital rights management (DRM) have been developed to prevent unauthorized use of content. DRM is used, for example, by digital media publishers to allow them to control the duplication and dissemination of their proprietary content. Potential problems of DRM include potential vulnerability to attacks and overprotection of content by preventing “fair use.” In addition, DRM may not be particularly useful or desirable, as an individual content creator may lack the ability to institute DRM measures, and access limitations generally run counter to the paradigm of free distribution of content among individuals.
Schemes exist for the digital watermarking of content, such as JPEG images or video files. Some conventional visual watermarking techniques, for example, embed identifying data within a compressed image or video file. Typically, the embedding is done in a manner that minimizes the creation of visual artifacts when an image is generated from the compressed file. While such techniques may be effective in maintaining the identity of content, they may be limited in their applicability.